CIUDAD JUAREZ, MEXICO -- To meet with Héctor "Teto" Murguía, the leading candidate for mayor of the city dubbed the deadliest in the world, a visitor parks at Murguía's paint factory, watched over by bodyguards with automatic rifles, then passes through three sets of steel vault doors into a windowless office.

"Welcome to the bunker," his press secretary says.

Elections in 12 Mexican states Sunday are taking place across a tense landscape of escalating violence and widespread fear that drug cartels are burrowing ever deeper into Mexico's politics, using corruption, intimidation and murder.

Murguía said, "I fear only God." But he also said he's not an idiot. "The security is for my family." He declined to reveal how many children he has.

On Wednesday, authorities discovered a headless corpse nailed to a tree near his home.

The 57-year-old candidate is a tough old-school politician, pugnacious with the press and popular among the city's poor, who likes to kiss babies and give away bags of cement. He is a wealthy businessman -- a land developer and factory owner -- from a prominent family. He served as mayor from 2004 to 2007.

His chief of police, who was a friend and business partner, was arrested shortly after Murguía's term ended for smuggling more than 900 pounds of marijuana across a bridge into neighboring El Paso.

Voters in Sunday's election are being asked: Is Murguía linked to the drug-smuggling mafias that have turned Ciudad Juarez into "Murder City," where warring gangs of street-corner thugs and professional contract killers routinely execute a dozen people a day?

Murguía's main opponent, César Jáuregui, a baby-faced 43-year-old lawyer and lifelong political operative, said the former mayor is dirty and, at the very least, has ties to organized crime.

Billboards put up across the city by the Jáuregui campaign shout: "Reject the criminals -- no more narco-politicians!"

On Monday morning, as Jáuregui was stumping in downtown Juarez, shaking hands with drivers stopped at traffic lights, his cellphone rang with the news that Rodolfo Torre Cantu, the front-runner for governor of the border state of Tamaulipas, had been assassinated minutes earlier by armed commandos. Cantu's brother is now running in his place.

"We are competing against people with a very bad history," said Jáuregui's wife, Angelica Morena, who was passing out campaign fliers. "They are people who associate with very bad people. So I'm afraid for him because I don't want anything to happen to him."